Contributor credits, SVG prefetch, integrate Xiaomi MiMo from PR #4

- Runs gain a contributor field (GitHub username); the site renders an
  avatar chip linked to their profile next to each run's notes, and CI
  validates the field. All existing runs are attributed.
- SVG variants of a case are prefetched during idle time, so switching
  model tabs swaps images without a network hiccup.
- Xiaomi MiMo v2.5 Pro (Claude Code, max effort) integrated from PR #4
  with both case runs and provenance notes; README registry tables
  updated.

Co-authored-by: DuJiabao <Jiabao.du@Yunzhisun.com>

models/composer-2-5.json

@@ -9,7 +9,8 @@
       "note": {
         "zh": "在 Cursor 中以 Composer 2.5 生成；本页为修复版（改 1 行）+ 补一个小功能。问题：第 1152 行水平速度先乘 speed*dt，位移时又乘一次 dt，实际步速只有设计值（5 格/秒）的约 1/60。修复前：走路如蜗牛、跳跃下落却正常；沙漠雪地等群系与神话建筑实际走不到，体感像「切换不了场景」——游戏本无传送功能，群系需步行抵达。原因：X/Z 轴把「每帧位移」当「每秒速度」存入 velocity，与 Y 轴语义不一致。去掉一次 dt 后步行恢复 5 格/秒。另外它确实生成了精灵螺旋塔、龙神殿、天空遗迹三处景点（也画在小地图上），但原版只能徒步抵达——已补加按 G 依次瞬移到三处景点的功能，开屏说明里也加了一行。",
         "en": "Generated with Composer 2.5 in Cursor; fixed build (1 line changed) plus one small addition. Bug: line 1152 multiplied horizontal velocity by speed*dt, then displacement multiplied by dt again, leaving walking at ~1/60 of the designed 5 blocks/s. Before the fix: walking crawled while jumping/falling felt normal, and biomes or mythic structures were virtually unreachable — which read as \"scene switching is broken\" (there is no teleport; biomes are reached on foot). Cause: X/Z stored per-frame displacement in a per-second velocity field, inconsistent with the Y axis. With one dt removed walking is back to 5 blocks/s. It does generate three landmarks (Elven Spiral Tower, Dragon Temple, Sky Ruins — also drawn on the minimap) that were only reachable on foot, so a G-key cycle-teleport to them was added, with a line in the start screen."
-      }
+      },
+      "contributor": "Nagi-ovo"
     }
   }
 }